Immunological Transfusion Reactions

ㅤ	Febrile Non hemolytic transfusion reactions
Occurrence	M/c
Within	Within 6 hours
Mechanism	• Graft-versus-host response • Anti-WBC and anti-HLA antibodies • Cytokine accumulation in stored blood
R/F	• Multiparous women donors • FFP donors
Presentation	• Fever and chills • ± Mild dyspnea
Treatment	• Antipyretics • Antihistamines • Stop transfusion if severe
Prevention	• Use leukoreduced product

ㅤ	Anaphylactic	Allergic / Urticarial
Within	Seconds to minutes	Within 2–3 hours
Mechanism	Type I hypersensitivity	Type I hypersensitivity
R/F	Isolated IgA deficiency	ㅤ
Presentation	• Shock • Respiratory distress • Angioedema	• Urticaria • Flushing • Pruritus
Treatment	• Stop transfusion • Epinephrine	• Stop transfusion • IV fluids
Prevention	• Use IgA-deficient plasma • Use washed RBCs	ㅤ

ㅤ	Acute Hemolytic	Delayed Hemolytic
Within	Within 24h	> 24h (usually ~2 weeks)
Mechanism	Type 2 Hypersensitivity • ABO incompatibility • Preformed IgM • Complement-mediated IVH	• Anamnestic IgG response to RBC antigens • Prior sensitization present • Extravascular hemolysis • via reticuloendothelial system
Presentation	• Fever, chills • Flank/back pain • Sense of impending doom • Hemoglobinuria • DIC, renal failure • Coombs’ test positive • Pink plasma	• Mild fever • Hemolytic anemia • Coombs’ test positive • New antibody screening positive
Treatment	• Stop transfusion • IV fluids aggressively	• Supportive care • May need additional transfusion

Feature	TRALI	TACO
ㅤ	• M/c cause of death post blood transfusion • M/c with FFP	ㅤ
Time interval	• Within 6 hours	• Within 12 hours
Predisposing	• Multiparous women donors • FFP donors	• Predisposing organ failure ↳ Cardiac or renal dysfunction
Etiopathogenesis	• Antibodies to HLA-II • Anti-neutrophilic antibodies/ • Anti-leukocyte antibodies Two-hit model ↳ Neutrophil priming in Pulm. Vasculature ↳ Activation by donor antileukocyte antibodies ↳ Pulmonary edema	• Volume overload
Clinical Presentation	Non-cardiogenic pulmonary edema Symptoms: • Fever, dyspnea Signs: • Hypoxemia, respiratory failure • Hypotension Chest x-ray: • B/L pulmonary infiltrates. D/D: • ARDS	Symptoms: • Dyspnea, cough Signs: • Evidence of circulatory overload: ↳ Hypertension ↳ Tachycardia Chest x-ray: (N).
Neck veins	Unchanged	Distended
Blood pressure	Hypotension	Hypertension
Treatment	Supportive care	• O2 support • IV diuretics • Phlebotomy
Response to diuretics	Inconsistent	Significant improvement